The present invention relates to a silver halide photographic light-sensitive material capable of forming a dye image improved in fastness to heat or light and free from stains.
A dye image formed by a silver halide photographic light-sensitive material is required not to discolor nor fade during long-time storage at high temperature and humidity. Also, the non-color-forming portion of a light-sensitive material is required not to get yellow stains (hereinafter referred to as "Y-stains") when exposed to light, heat or moisture.
For forming magenta dyes, couplers consisting mainly of pyrazolone, pyrazolobenzimidazole, pyrazolotriazole or indazolone are commonly employed.
As compared with yellow and cyan dyes, magenta dyes are more subject to fading by exposure to light. In addition, the problem of Y-stain formation is more serious in magenta couplers than in yellow and cyan couplers.
Meanwhile, 1,2-pyrazolo-5-ones are widely employed as the magenta coupler. They are not satisfactory in color reproducibility, since a magenta dye formed therefrom has unnecessary secondary absorption at about 430 nm, besides primary one at about 550 nm. Various studies have heretofore been made to minimize such secondary absorption.
For instance, U.S. Pat. No. 2,343,703 and British Patent No. 1,059,994 each describe a magenta coupler consisting of 1,2-pyrazolo-5-one having an anilino group at the 3-position. This coupler is suitable for use in preparing photoprints for direct visual appreciation, since a dye formed therefrom has minimized secondary absorption. However, it is considerably defective in image preservability; a magenta dye formed therefrom readily fades by exposure to light, and a large part of the unreacted portion of the coupler tends to become Y-stains.
The following compounds were also proposed as the magenta coupler capable of forming a magenta dye having minimized secondary absorption at about 430 nm; pyrazolobenzimidazoles (British Patent No. 1,047,612), indazolones (U.S. Pat. No. 3,770,447), 1H-pyrazolo [51-c]-1,2,4-triazole (U.S. Pat. No. 3,725,067, British Patent Nos. 1,252,418 and 1,334,515), 1H-pyrazolo [1,5-b]-1,2,4-triazole (Japanese Patent Publication Open to Public Inspection, hereinafter abbreviated as "Japanese Patent O.P.I. Publication", No. 171956/1984, Research Disclosure No. 24,531), 1H-pyrazolo [1,5-c]-1,2,3-triazole (Research Disclosure No. 24,626), 1H-imidazo [1,2-b] pyrazole (Japanese Patent O.P.I. Publication No. 162548/1984 and Research Disclosure No. 24,531), 1H-pyrazolo [1,5-b]pyrazole (Japanese Patent O.P.I. Publication No.43659/1985 and Research Disclosure No. 24,230), and 1H-pyrazolo [1,5-d] tetrazole (Japanese Patent O.P.I. Publication No. 33552/1985 and Research Disclosure No. 24,220). Of the above couplers, especially preferred are 1H-pyrazolo [5,1-c]-1,2,4-triazole, 1H-pyrazolo [1,5-b]-1,2,4-triazole, 1H-pyrazolo [1,5-c]-1,2,3-triazole, 1H-imidazo [1,2-b]-pyrazole, 1H-pyrazolo [1,5-d] pyrazole and 1H-pyrazolo [1,5-d] tetrazole. They are capable of forming a dye having much smaller secondary absorption at about 430 nm than that formed from the 1,2-pyrazolo-5-one coupler having an anilino group at the 3-position, and eventually have more improved color reproducibility than the 1,2-pyrazolo-5-one coupler, and are almost free from the Y-stain formation problem.
However, an azomethine dye formed from these couplers has considerably poor light fastness, and readily discolors when exposed to light. Therefore, these couplers are unsuitable for use in light-sensitive materials for color photoprints, and none of them has been practically used for that purpose
Japanese Patent O.P.I. Publication No. 125732/1984 discloses a method for improving the light fastness of a magenta dye image formed from 1H-pyrazolo [5,1-c]-1,2,4-triazole by using a phenol compound or a phenyl ether compound in combination with this coupler. This method, however, is still insufficient to prevent a magenta dye image from fading, and almost impossible to prevent it from discoloring in light.